1. Field
Embodiments of the present invention relate to an energy storage system.
2. Description of the Related Art
Recently, renewable energy is emerging due to the depletion of fossil fuels and environmental issues. The renewable energy uses natural energy such as sunlight, solar heat, wind power, tidal power or geothermal heat, and electricity generating systems mainly using sunlight are being widely and practically applied.
A renewable energy generating system is a system that supplies a power of renewable energy generator to a load or a grid. When the power produced by a renewable energy generator is less than the power consumed by a load, all the power available from the renewable energy generator is consumed by the load, and an insufficient power is supplied through a grid. When the power produced by the renewable energy generator is greater than the power consumed by the load, a surplus power that is not consumed by the load among the power produced by the renewable energy generator is supplied to a grid as a reverse flow power.
A power storage system is a system that converts power to a physical or chemical energy and stores the energy. The power storage system is connected to the grid, receives power (“night power”) from the grid during night, stores the received power, and uses the energy of the received power during a daytime. Further, an energy storage system supplies an emergency power during blackout, during which electricity is not supplied through the grid.
Such an energy storage system combines a renewable energy generating system and a power storage system, and stores the surplus power from the renewable energy generator and night power from the grid in the power storage system. In the energy storage system, power generated by the renewable energy generating system may be stored in the power storage system, or may be provided to the load and/or the grid.